Method for drilling large diameter holes



United States Patent [72] Inventor JackV.Tedrow c/o US. Army Terrestrial Sciences Center, P.0. Box 1601, Fairbanks. Alaska 99701 [21] ApplNo 812,165 [221 Filed Aprill,l969 [45] Patented Nov. 10, 1970 [54] METHOD FOR DRILLING LARGE DIAMETER HOLES 2 Claims, 5 Drawing Figs.

[52] U.S.Cl 175/57 [51] lnt.C1. E2lb 7/00 [50] FieldolSearch l75/57,62, 91,96

[56] References Cited UNITED STATES PATENTS 936,350 10/1909 Palmer l75/57X /o& 4-

i i i i Z r z 1 E i I a 2,641,444 6/1953 Moon 3,185,226 5/1-965 Robbins l75/57X 3,232,360 l/l966 Dickinson 175/62 3,310,124 3/1967 Farmer l75/57X Primary Examiner David H Brown Atrorney- Harry M. Saragovitz, Edward J. Kelly. Herbert Berl and Lawrence E. Labadini casing which is borne by the traversing bar and by pressure exerted against the pilot shaftv is 15111: s ms Pa ltegted Nov. 10, 1970 Q Sheet 1 of 3 V lllllllllllllllllll IJII;

Jaom V Tedz oxa,

whim v 4; Mm/7 Pat ente d Nov. 10, 1970 3,539,023

' SPECIFICATION The invention described herein may'be manufactured;used,

and licensed by or for theGovernrnent for governmental'purposes without-the payment to meet any royalty thereon.

This invention relates to a novel'method andapparatus for drilling. large cylindrical openings or holes in the .earth..Such openings can be used for numerouspurposessuch as underground silos or storage compartments, concealed gun mounts, imbedded missile pads, mining-shafts.and the like. In addition, my invention could be used in underground rescue operations to retrievetrapped miners. i

In the past, there has been a problem with drilling large diameter holes or boreholes in remote. areas. In addition, it has been very difficult to move this drilling equipment quickly from one place to another. The main :reason for these problemsis the extremesizeand weight required in these large diameter hole drills. It is notuncommon for the drill collar on one of these conventional drills toweight 300,000 pounds. This extreme size and weight makes it 'very difficult and expensive to move the drilling equipment and it is almost impossible to take this-equipmentintoremoteareas.

I have discovered that'theabove problem may be solved by eliminating the massive drill collar used by'conventional drill rigs. This is accomplished by drilling several small diameter holes, the sum being a largesdiameter hole, which does not require the drill collar. My invention would make it possible for the drilling equipment to be moved or flown into remote areas and to be flown from one place to. another in a short period of time.

Inview. of the above, the primary object of my invention is to provide a novel method and apparatus for drilling .a large diameter hole.

A further object of this invention is to provide a novel method and apparatus for drilling large diameter holes whereby this may be accomplished without the use of extremely heavy drilling equipment.

A further object of the-invention is to provide a nove method and apparatus for drillingnlarge diameter holes whereby. the, equipment may be -moved in a reasonable fashion; a

A further object of my invention is to provide a novel method and apparatus for drilling large diameter holes whereby a series of contiguous small'diameter holes form a large diameter hole.

With the-foregoing objects in view and suchother objects and advantages as will becomeapparent to those skilled in the art to which this invention relates as this specification proceeds, my invention consists essentially in the arrangement and construction of parts all as hereinafter more particularly described, reference being had toaccompanying drawings.

FIG. 1 is a side elevation showing the over-all apparatus of this invention.

FIG. 2 is a top section taken xalongthe line 2-2.

FIG. 3 is aside section taken along line 3-3 in the direction of the arrows and showing in greaterdetail a portion of the structure illustrated in FIG. 1.

FIG. 4 is a top view taken along line 4-4.

FIG. 5 is a top view showing a second embodiment using the principles of the-present invention.

Referring now to FIG. 1, a pilot. hole 1 is drilled into the earth to a depth slightly greater than the desired depth of the large, Lie. ,6-.-25 feet, diameter hole. This pilot hole could be drilled by any suitable means known in the art such as a rotary rock drill. Next a small-diameter anchor pipe 2, having an outside diameter between 2 to 6 inches, is placed down the pilot hole and anchored to the bottom of pilot hole 1. Anchoring can be accomplished by any one of several known means such asa pa cker assembly 4. If the bottom of the anchor pipe is in rockfthe packer assembly will hold.lf.the anchor pipe is in firm soil, an underreamer should be usedto ream out about 200 feet at the bottom of the pilot hole and then asealingadditure such as plastic is pumped in. It should be noted that after anchor pipe- 2 is anchored to the bottom of pilot hole I there will be a portion of the anchor pipe which will extend above the earths surface f'or purposes. which will be explained later.'

The drill assembly, as shown .in FlG., 1 ;-consists of two identical augers 6 and 7 and a centeriaugerfi .which is located over and rotatable about said'anchor pipe 2 as shown. Augers 6 and 7 are connected to power subs l0 and 12 respectively I and auger 8 is connected to a'=hydraulic power swivel 14..

Power subs l0 and .l2supply rotary motion to theaugers through shafts l6 and 18 respectively-and power subs l0-and 12 may be of any commercial type knownin the art such as the Bowen PS-3 Power Sub which is'manufactured by Bowen Tools, Inc., Houston, Texas. Augers in the present embodiment have a 36 inch diameter but such small-diameter augers may range from 6 inches to 36 inches in diameter.

Rotary power is supplied to auger 8 from hydraulic power swivel 14'through shaft 20. Hydraulic power swivel 14 may be. of any commercial type known in the art.

Hydraulic power swivel 14 is connected to a hydraulic jack 22 which is connected to a hydraulic slip 24. As is shown in FIG. 1, anchor pipe 2 passes through hydraulic powerswivel l4, hydraulic jack 22 and hydraulic slip 24. Hydraulic jack 22 may be of'any'commercial type known in the art and should have a 5 foot stroke and a 100 ton capacity for best operation.

Hydraulic pressure is supplied to power sub 10 by hydraulic lines26and 28 and to power sub 12 by hydraulic lines 30 and 32. Likewise, hydraulic power is supplied to hydraulic powerswive l.l4. by lines 34 and 36. All of these hydraulic lines are:

jacking bar 38. Bar .38 contains slots and 42 as shown in FIG. 2. Shafts l6and 18 fit within slots 40 and 42 respectively and this allows power subs l0 and 12 to traverse along bar 38 jack 46 as shown in FIG. 2.

Bar 38 is attached to hydraulic power swivel l4 and also to U-bars 48 and 50. U-bars 48 and 50 are in turn connected to, auxiliary hydraulic jacks 52 and 54. FIG. 3 shows how power sub 10 can traverse along bar 38 to its most extended position as shownby power sub 10a.

Auxiliary hydraulic jacks 52 and 54 are connected to a bar 56. Bar 56 is connected to hydraulic slip 24 and also to casing jacking rings 58 and 60. Casing jacking rings 58 and 60 are attached to a casing 62. In addition to rings58 and 60, casing jacking rings 64, 66, 68 and 70 are attached to casing 62 as shown in FIG. 4. These rings continue around casing 62 at uniform intervals and they wouldbe located in a continuous manner around casing 62 if it were shown. Bar 56 is attached to rings 58 and60 in such a manner that it may be unattached and then reattached to another pair of jacking ringssuch as rings 64 and 70. This could be accomplished in a manner such as attaching bar 56 to rings 58 and 60 by removable screws.

' The operation of my invention as above described is as follows: After the anchor pipe is secured as described above the drilling of the large diameter hole begins Anchor pipe 2 will extend above the earths surface an amount slightly greater than the height of the drilling apparatus. The drilling apparatus is then attached to anchor pipe 2 and auxiliary hydraulic jacks 52 and 54 and hydraulic jack 22 are in the contracted or up position. Next hydraulic slip 24 is locked onto anchor pipe 2. Augers 6, 7 and 8 are then set in rotary. motion by power supplied by power subs l0 and 12 and by hydraulic power swivel 14 respectively. The augers are then forced down into the earths crust by engaging hydraulic jack 22 and auxiliary jacks 52 and 54 toward their extended positions as shown in FIG. 1. The reaction needed for the action of forcing the augers down comes from the fact that the hydraulic slip is secured to anchor pipe 2 which is anchored into the ground. Also, after the drill assembly has progressed down into the earth for a short distance a section of casing 62 may be placed in the hole and attached to bar 56 at jacking rings 58 and 60. The casing will give additional weight to the assembly to force the augers down during drilling.

After augers 6, 7 and 8 have drilled into the earth up to bar 38, hydraulic jack 22 and auxiliary jacks 52 and 54 are moved into the contracted or up position, thus raising augers 6, 7 and 8 leaving holes in the earth where these augers had drilled. Next hydraulic jacks 44 and 46 are set in motion and power subs 10 and 12 are moved along bar 38 away from anchor pipe 2. Power subs l and 12 should be moved enough so that augers 6 and 7 are just past the previously drilled hole. Next the augers are forced into the earth as described above and the above sequence is repeated. This above described operation will continue until the augers have drilled holes along a line under bar 38 and when power subs and 12 are in the outer position as shown by 10a and 12a in FIG. 1. As stated above, FIG. 3 shows how the power sub 10 will go under U-bar 48 to allow holes to be drilled under the outer edge of bar 38. This is also true of power sub 12 and U-bar 50.

After a line of holes has been drilled under bar 38 as described above, hydraulic jack 22 and auxiliary jacks 52 and 54 are again put in the contracted or up position. Next bar 56 is detached from rings 58 and 60 if casing 62 is being used. Hydraulic power swivel 14 is then engaged and the whole drilling assembly is rotated in either a clockwise or counterclockwise direction. If the direction was clockwise then the drill assembly would be moved until bar 56 was under rings 64 and 70. Next, bar 56 is attached to rings 64 and 70 in the same manner as it was attached to rings 58 and 60.

After the drill assembly is turned, power subs 10 and 12 are moved to their position, shown as FIG. 1, by hydraulic jacks 44 and 46 Once again the drilling procedure is repeated along the new position of bar 38. After the new line of holes are drilled the whole assembly is rotated again. This drilling of small holes with augers 6 and 7 is continued until a large diameter hole is formed.

The loose earth created by the drilling process could be removed in any one of several conventional ways. One method would be to use a jet engine and create a venturi system whereby the jet engine would create a vacuum which would pull the loose dirt up through conduits (not shown) which would extend into the hole.

Once the large hole has been formed from the small holes, hydraulic slip 24 is released from anchor pipe 2 and the whole drill assembly plus casing is lowered to a new position so that augers 6, 7 and 8 may once again drill into the earth. This sequence of operations would be continued until the desired depth of the large diameter hole was achieved.

FIG. 5 shows a second embodiment of my invention. Here again the principal is to drill a large diameter hole by drilling a series of small diameter holes. The basic operation and drill assembly would be the same as described above but in this embodiment an X-shaped bar would be used and four power subs and four augers.

An X-shaped bar 72 would replace bar 38 of the above assembly and on this bar would be located power subs 74, 76, 78 and 80. Power sub 74 is moved along one position of bar 72 by hydraulic jack 82. Likewise power subs 76, 78 and 80 are moved along their positions of bar 72 by hydraulic jacks 84, 86 and 88 respectively. Anchor pipe 2, hydraulic jack 22 and casing 62 will be identical as described above. Power sub 78 will be supplied hydraulic power through lines 98 and 100. Likewise, sub 80 by lines 102 and 104, sub 74 by lines 106 and 108, and sub 76 by lines 110 and 112. Also slots I14, I16, 118 and 120 are provided in bar 72 so that power subs 74, 76, 78 and 80 respectively may move back and forth along their position of bar 72. Ubars I22, 124, 126 and 128 are located on the end position of X-shaped bar 72 and auxiliary jacks (not shown) will be located above these U-bars.

The operationof this embodiment would be the same as the drilling apparatus explained above. The main advantage in this embodiment being that the small holes may be drilled with one-half the number of operations as required by the primary invention. Therefore, the large diameter hole could be dug faster since more augers are employed.

While I have shown and described a workable form of my invention, I wish it to be specifically understood that the same may well be modified without departure from the scope and spirit of the appended claims.

I claim:

I. The method for drilling large diameter cylindrical boreholes in the earth s crust, comprising:

a. sinking and anchoring a small-diameter anchor pipe into the earth's surface along the vertical axis of the intended cylindrical borehole;

b. mounting a drilling assembly on said anchor pipe so as to be rotatable about said anchor pipe, said assembly having a plurality of small-diameter downwardly directed drilling augers, including a central auger located over and rotatable about said anchor pipe and lateral augers on opposite sides of said central auger and adapted to move laterally along a traversing bar between said central auger and the peripheral edge of said borehole;

e. boring holes with said augers while applying a downward pressure on said devices relative to the upper end of said anchor pipe;

d. alternately lifting and lowering said drilling assembly and moving said lateral augers to different positions to cut contiguous holes in the earth; and

e. rotating alternately said drilling assembly about said anchor pipe to cut contiguous holes over the entire face of the borehole.

2. The method according to claim 1 comprising the additional step of supporting the weight of the borehole casing on said drilling assembly. 

